1. Field of the Invention
The present invention belongs to the technical field of bandwidth allocation technology.
2. Description of the Related Art
Bandwidth allocation technology is technology that, when a memory resource is shared by a plurality of master devices, guarantees memory access at a particular bandwidth for the plurality of master devices. The bandwidth allocation can be realized with arbitration control performed by an arbitration device. Following is a description of bandwidth allocation with a conventional arbitration device. With conventional bandwidth allocation, bandwidth control is realized by providing counters for bandwidth control in an arbitration device that attempts to arbitrate among a plurality of master devices. These counters are provided corresponding to each of the plurality of master devices, and if the arbitration device permits memory access by a particular master device, the count value for that master device is incremented. Two parameters, an upper limit value and a cycle number, are provided in this counter, and if the count value of the counter is less than the upper limit value, the arbitration device permits the access request from the master device. Conversely, if the count value is more than the upper limit value, the access request from the master device is not permitted. On the other hand, the cycle number prescribes a period after which the count value of the counter is automatically decremented. After the count value of the counter has reached the upper limit value, and until the period indicated by the cycle number elapses, the count value of the counter maintains the upper limit value, causing the access request of the master device to not be permitted. If the period indicated by the cycle number has elapsed and the count value of the counter has become less than the upper limit value, an access request from the master device is again permitted. Here, when the operating frequency of the memory is f [Hz], it is possible to operate the master device at a bandwidth prescribed in advance if an upper limit value U and a count value C are set so as to satisfy the expression below.Bandwidth allocated to master device=operating frequencyf×counter upper limit value U/cycle number C 
The conventional technology includes the technology described in Patent Document 1 and Patent Document 2.
Patent Document 1: Japanese Patent Application Publication No. 2004-5589
Patent Document 2: Japanese Patent Application Publication No. 2002-304368